The present invention relates to communication among vehicle controllers on a serial bus. It finds particular application in conjunction with communicating engine control instructions among the vehicle controllers and will be described with particular reference thereto. It will be appreciated, however, that the invention is also amenable to other applications.
Vehicles, for example heavy vehicles such as trucks and buses, increasingly utilize various controllers on a vehicle data bus (e.g., SAE 1939) for controlling different functions on the vehicle. In such configurations, each of the controllers includes a specific identifier. Then, a request to increase a torque and/or speed of the vehicle's engine may be communicated in the form of a message from one of the controllers to another one of the controllers via the data bus. Messages transmitted along the data bus include identifiers of both the originating controller and the destination controller. The identifiers are used as the messages are routed along the data bus from the originating controller to the destination controller.
It is becoming more common for heavy vehicles to include adaptive control with braking (ACB) systems. ACB systems are used for controlling a speed of a vehicle to maintain a minimum distance behind another vehicle. Currently, an engine control mode request message (e.g., a torque increase request message or a torque decrease request message) such as a torque/speed control (TSC1) message is transmitted from the ACB system to an engine controller. However, since engines of different models and makes have different levels of support for TSC1 message requests from an ACB system, only certain engines respond to a TSC1 message from an ACB system.
The engine controller may also receive additional control mode request messages from other systems on the vehicle. These additional control mode requests may conflict with the control mode request the engine controller receives from the ACB system. The engine controller may respond unpredictably upon receiving conflicting control mode requests.
The present invention provides a new and improved apparatus and method which addresses the above-referenced problems.